Just to document a bit this thread, here is a post by Paris-based American "Gambist" Jonathan Dunford, about viola da gamba uses besides period music:

Judith Davidoff in New York has a huge database of contemporary classical music for the viol. There's even a competition sponsored by the VDGSA for the best contemporary music for the instrument.
In the "pop" category there are a few French movie soundtracks that feature the viol. The first of course is "Tous les Matins du Monde", but we participated in another film "Caprices d'un Fleuve" which combined the viol with pop singers and African instruments.
In the "way out" category I participated in a mixture of Chinese and European music for a new CD "Vepres de la Vierge en Chine", for K617. For those interested it's for sale here : http://www.amazon.fr/exec/obidos/ASIN/B00019IC5K/402-3016478-8274502
I also participated in a "free jazz" cd to be released soon. I know that my collegue Vittorio Ghielm has made a jazz recording too.
There also is an electric gamba :details here :http://www.ruby-gamba.com/mainpage.html
A French builder Hubert Dufour is going to show his version (more wood and more like a "real" gamba) at the French music fair in Paris in April.
Another collegue here Christine Payeux has more or less given up on "old" music. She plays the viol in a rock band!